Computer buying advice - graphics capabilities of 16" MBP vs iMac for online teaching

Hi all,

I’m hoping to get some advice as I think through buying a new computer. I have a late 2014 27" iMac and a 2018 13" MacBook Pro. An important discovery over the summer was despite the wide age gap between the two computers, my MBP just couldn’t keep up with my needs while teaching over Zoom (I use a BlackMagic ATEM Mini, I screen share from my iPad, I have 60-80 students). I’d have serious video lag, choppy animation, and fans blazing almost immediately. My old iMac, on the other hand, handled all this without any issue.

My guess is that this is because of different CPUs between the two, or because of a dedicated GPU in the iMac, but I’m genuinely not sure (could just be the laptop form factor or something else). My question to you all is: would a 16" MBP act more like my iMac, or more like my MBP, in terms of heavy videoconferencing/screensharing needs? Should I just go with a newer iMac and be on the safe side, or is a portal laptop that is capable of all this possible?

Any guidance would be greatly appreciated - I’ve never hit against performance ceilings on my computers until switching heavily to online teaching, but now need to adapt, so would really appreciate y’alls expertise!


It sounds like the difference is probably because the 2014 iMac has a discrete GPU, while the 13" MacBook uses Intel integrated graphics built into the CPU. If that’s the case, the 16" has a discrete GPU, so it would presumably behave more like the iMac than the 13".

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same experience,
I hardly recall hearing the fans on my previous iMac. Now, my MBP fans are on almost all the time, and I have an eGPU.

I’d say go again with an iMac, CPUs are better, less heating, better ventilation, plus you can add RAM. I’m seriously considering going back to iMac soon.

Re screenshare: I use Duet app, works great and uses way way way less CPU than sidecar.


Another plus with the iMac is people won’t be looking up your nose, since the camera is higher.
More screen real estate, etc.


This is all super helpful, thanks! @Kraftwerk I’ve been using Luna Display which has been quite good in that respect. @JohnAtl I use an external webcam so not worried about the angle, but am worried about graphics capabilities because on my 13" it starts stuttering in the middle of Zoom meetings.

Would love others to weigh in as well!

Just so I’m clear - you have a dedicated external GPU and it’s still blasting fans?

just realized we both have a 2018 MBP.

From my experience, the bottleneck is the CPU in the MBP.

you have a dedicated external GPU and [the MBP] it’s still blasting fans?

yup, I do work in graphics, and expected the eGPU (8 GB AMD Radeon) would take most of the graphics workload off of my MBP.

The eGPU barely registers any usage, never goes higher than 7%, its fans turn on once or twice a day for a brief couple seconds.

So, in summary: the eGPU works great while the CPU struggles a lot, fans ablaze.

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Got it. Super helpful! Is yours a 13" or 16"?

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It has been noted here before that Zoom, in particular, causes the MBP to heat up, especially when using external displays.

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it’s a 2018 13" MBP

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To chime in the opposing side to an iMac … I have a 16in MBP at 2.4GHz 8 core i9 with 32 GB and the Graphics 630/1536 MB.

I run Zoom over WiFi + Curio + other apps (PDFExpert, Maple, Igor Pro) while projecting through a USB-C to HDMI and inputting to a WiFi headset.

Yes, my system gets “warm”. But my fans do not spin loudly.

I also run Zoom while at my office or home desk with a second monitor connected through an Anker hub (2x USB + USB-C + HDMI + ethernet + cards). My monitors are either Quad resolution or one step lower (i.e. not 4K). In both cases, I have the computer sitting on an active cooling platform (meaning that the computer has a fan under it).

Again, my system gets “warm”, but my fans do not spin loudly.

Finally, I am currently sitting in a university building overseeing a late night chemistry lab. I just ran the Zoom sessions with the on-line team members partnering with the in-lab team members. I also have everything with me on my MBP when I do my lectures, so that I all I need to do is plug into the HDMI projector. I do not need to run the hard-wired Windows systems provided by my university to do my lectures. With this in mind, as an instructor, I can strongly emphasize not to understate/underestimate the advantages of being able to be fully portable with your computer on a moments notice.



Hmmm, so in that case I’m wondering if the 16” would fare significantly better (@DrJJWMac suggests that it might).

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thanks for your observation DrJ.
Mine is a 2.3 Dual-core i5, and I guess @tedsvo is as well. Baffled that these are the “Pro” offerings and struggle

@tedsvo tried lowering the resolution?
I lowered mine to a non-retina and now it feels blazingly FAST!
Screen Shot 2020-11-15 at 8.59 AM

There was a thread in Hacker News about speeding up underpowered laptops, and I remembered I have Quickres installed, gave it a go, and now it feels like brand new!

This is really good to know @Kraftwerk! I went out on a limb and bought a M1 Macbook Pro and it seems(?) like all my problems have been solved. Super smooth and never seems to run hot. I will be pushing it pretty hard in the next week so will see how well it holds up.


I have a similar system (64GB, 2x4K external displays, 5500M GPU) and spend half my day in Zoom. The behaviour that I see is similar to yours: the system gets warm and there is low to moderate fan noise. If I push the system the fans do spin up, but Zoom doesn’t push the system.

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